The present invention is directed generally to the fastener arts and more particularly to a novel fastener-carrier system including a carrier strip and one or more fasteners for use in coupling together a pair of workpieces, for example.
The fastener-carrier system of the invention is particularly adapted for use in joining a pair of workpieces at abutting, substantially flat surface portions thereof. Such a fastener-carrier system is particularly useful, for example, in the automotive industry for joining panels to underlying support structures wherein access to the side of one of panels for deployment of a work took is difficult.
More specifically, such a fastener-carrier system may be utilized to affix a bumper to a mounting plate portion of a shock absorbing structure, of the type often utilized in impact-resistant bumper assemblies. In such applications, it should be recognized that a shank portion of the fastener must generally project through the bumper or other first workpiece so as to engage with a complementary aperture on the mounting plate or other second workpiece or underlying support member. As can be appreciated from the illustration of FIG. 1 the interior of the bumper does not provide adequate space for employment of tooling to hold the fastener in place. With the present invention the carrier system serves to maintain the fasteners in place and permit ease in joining the bumper to the mounting plate. Thereafter, the fastener may be used to secure the two workpieces together, in the case where a threaded fastener is used, by engaging a complementary internal threaded nut-type fastener therewith and advancing the complementary fastener to grip the two workpieces tightly together.
It will be recognized from FIG. 1 that it is difficult and time consuming for the worker or assembler to perform such an assembly with conventional threaded fasteners. The assembler must first locate and insert the fastener(s) through one or more apertures in the first workpiece, and then engage the fastener with some form of tool to hold the fastener(s) in place while locating the aperture or apertures of the second workpiece. The whole assembly must then be held in place while starting the complementary fastener(s). The assembler must also hold each first fastener against rotation while starting and driving the mating fastener to assure the desired torque upon the second or mating fastener with respect thereto and the desired degree of gripping of the workpieces therebetween. In this regard, it will be recognized that an intermediate mating fastener cannot be utilized to initially position and hold the first fastener in place when the two workpieces are to be held in abutting relationship.
The prior art has proposed utilizing studs welded directly to one of the workpieces to solve the foregoing problems. However, this requires that the weld be substantially clean and flush with the surface, thereby requiring additional grinding or smoothing steps, to assure the desired flat and abutting condition of the two workpieces. Moreover, the welded stud has very little corrosion resistance in the area of its coupling or welding to the first or underlying workpiece. In automotive assemblies, it will be recognized that these structures are constantly exposed to potentially corrosive environmental conditions. Hence, the prior art system may fail due to corrosion of the critical welded areas of the stud.
Moreover, the weld must withstand a substantial amount of torque applied by the tool which applies the mating fastener or nut to the threaded shank of the stud. The axial force created as the mating fastener seats must also be accommodated by the weld. Failure and/or breakage of the stud relative to its mounting surface either during assembly or afterward due to stresses encountered during assembly is to be avoided.